It couldn't have come at a worse time - the Anzac Day blockbuster and grand final rematch against the Waikato Chiefs.

Brumby Jack throws up during Chiefs game. Photo: Supplied

The rumours started to circulate, the crowd started to heckle: "I thought he was a horse not a yak. Somebody get a gun."

Advertisement

But what caused it all? Was BJ really drunk like many thought?

The truth was much darker and much more sinister - Brumby Jack, for one night only, was actually a comedian. Shocking.

He was none other than Brumbies legend Clyde Rathbone's brother Dayne and his one night in the mascot's suit was designed as a present to cheer him up after a disastrous trial show of It's Me Mandela - a comedy show Dayne was working on to raise money for charity.

Suspicions should have been aroused when the stand-in Brumby Jack did his first cartwheel - the cartwheel of a clumsy comedian rather than a professional mascot.

Dayne has now revealed the full details behind his brief appearance in the horse suit in the latest edition of his YouTube series Dayne's World.

&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;nbsp;

Following the disastrous trial, Dayne says he sat in his room for days and was still sombre as his mum painted his face before a Brumbies match.

But the family had hatched a plan to cheer him up and the excitement built as game day approached.

Game day arrived and began with an interview with Fox Sports commentator Sean Maloney, but the usually jovial Maloney's face turned to shock and disbelief as events unravelled before his eyes.

Brumbies superstar David Pocock seemed envious of Dayne's opportunity: "I wonder what it will be like? I've heard it's pretty sweaty in there. Every time you kick off you hear Brumby Jack, so it's a big honour."

But no amount of training could prepare Dayne for the real thing.

The heat inside the suit under the glare of the bright lights. The pressure of performing in front of a massive crowd. Eventually Dayne overheated and reached bursting point.

He cut a lonely and dejected figure as he was led away down the players' race well before the end of the game.

Brumby Jack wasn't there to celebrate the Brumbies' win, but at least we now know why.